🚀 go-pugleaf

In article <1992Oct31.233148.8940@odin.corp.sgi.com> adams@chuck.dallas.sgi.com (Charles Adams) writes:
>In article <1992Oct30.193947.16978@sco.COM>, abhinava@sco.COM (Abhinav Aggarwal) writes:
>|> I have a rechargeable Ni-Cad battery. I would like to drain it
>|> to about 1-2 V (from 10V ) before I recharge it.
>|> 
>|> I plan to use a 500K ohm resistor to discharge a battery.
>|> Is this ok in terms of current and loads ?
>|> 
>|> Any other simple, cheap, and effective solutions ?
>|> 
>|> Please email me at aggarwal@sunee.uwaterloo.ca 
>
>Let's see, i=e/r
>           i=10v/500K
>           i=1/50,000 ampere
>           i=0.00002 ampere
>           i=20.0 microamps
>
>You didn't say what the amp-hr rating was, let's assume 1.0 amp-hr (small
>battery capable of 100 milliamperes for 1 hour).  (maybe medium).
>
>time=amp-hr/i= 1.0 amp-hr/20.0 microamps = 50,000 hours = 2083 days = 5.7 yrs
>
>the above just an approximation.  (if my math is right with assumptions i made)
>
>In my humble opinion (IMHO) i'd use a resistor of much smaller value.
>can you quote us the rating on the battery(ies)......
>

Aside from the annoyance of a long wait, why would you want to drain
a nicad battery like this?  That is the worst possible treatment you
can give to a nicad battery.  It also runs the risk of causing a
reverse charge to occur to cell(s) of a battery consisting of
a series string.  

Nicads should not be allowed to get below  1.0 volt per cell before
recharging.

Forrest Gehrke feg@dodger.att.com   k2bt